1. Field of the Invention
The present invention relates to a novel austenitic free-cutting stainless steel which has improved machinability without deteriorating corrosion resistance and hot workability.
2. State of the Art
There has been proposed and used various types of austenitic free-cutting steel containing mechinability-improving element or elements such as sulfur, selenium and calcium solely or in combination. Although these austenitic free-cutting stainless steel have good machinability, corrosion resistance and hot workability thereof are generally dissatisfactory.
We have investigated austenitic free-cutting stainless steel having not only good machinability but also satisfactory corrosion resistance and hot workability which are inherent in conventional austentic stainless steel.
It was our discovery that addition of a suitable amount of lead to the austenitic stainless steel is effective to improve machinability without deteriorating corrosion resistance. However, we encountered a novel problem that the hot workability of the steel is deteriorated in return for the improved corrosion resistance.